The synthesis of N,N′-disulfanediyl-bis(N′-((E)-benzylidene)acetohydrazide) from (E)-N′-benzylideneacetohydrazide and S8

Herein we report an oxidative coupling reaction for N–S/S–S bond formation from (E)-N′-benzylideneacetohydrazide and S₈ to furnish substituted N,N′-disulfanediyl-bis(N′-((E)-benzylidene) acetohydrazide). It provides a direct approach for the synthesis of disulfides with good yields.

Herein we report an oxidative coupling reaction for N–S/S–S bond formation substituted N,N′-disulfanediyl bis(N′-((E)-benzylidene)acetohydrazide). It provides a direct approach for the synthesis of disulfides with good yields.     

Reactive molecular dynamics simulation of the high-temperature pyrolysis of 2,2′,2′′,4,4′,4′′,6,6′,6′′-nonanitro-1,1′:3′,1′′-terphenyl (NONA)

2,2′,2′′,4,4′,4′′,6,6′,6′′-Nonanitro-1,1′:3′,1′′-terphenyl (NONA) is currently recognized as an excellent heat-resistant explosive. To improve the atomistic understanding of the thermal decomposition paths of NONA, we performed a series of reactive force field (ReaxFF) molecular dynamics simulations under extreme conditions of temperature and pressure. The results show that two distinct initial decomposition mechanisms are the homolytic cleavage of the C–NO₂ bond and nitro–nitrite (NO₂ → ONO) isomerization followed by NO fission. Bimolecular and fused ring compounds are found in the subsequent decomposition of NONA. The product identification analysis under finite time steps showed that the gaseous products are CO₂, N₂, and H₂O. The amount of CO₂ is energetically more favorable for the system at high temperature or low density. The carbon-containing clusters are a favorable growth pathway at low temperatures, and this process was further demonstrated by the analysis of diffusion coefficients. The increase of the crystal density accelerates the decomposition of NONA judged by the analysis of reaction kinetic parameters and activation barriers. In the endothermic and exothermic stages, a 20% increase in NONA density increases the activation energies by 3.24 and 0.48 kcal mol⁻¹, respectively. The values of activation energies (49.34–49.82 kcal mol⁻¹) agree with the experimental data in the initial decomposition stage.

The bimolecular and fused ring compounds are found in the high-temperature pyrolysis of NONA using ReaxFF molecular dynamics simulations.     

P-stereocontrolled synthesis of oligo(nucleoside N3′→O5′ phosphoramidothioate)s – opportunities and limitations

3′-N-(2-Thio-1,3,2-oxathiaphospholane) derivatives of 5′-O-DMT-3′-amino-2′,3′-dideoxy-ribonucleosides (_NOTP-N), that bear a 4,4-unsubstituted, 4,4-dimethyl, or 4,4-pentamethylene substituted oxathiaphospholane ring, were synthesized. Within these three series, _NOTP-N differed by canonical nucleobases (i.e., Ade^Bz, Cyt^Bz, Gua^iBu, or Thy). The monomers were chromatographically separated into P-diastereomers, which were further used to prepare N_NPSN′ dinucleotides (3), as well as short P-stereodefined oligo(deoxyribonucleoside N3′→O5′ phosphoramidothioate)s (NPS-) and chimeric NPS/PO- and NPS/PS-oligomers. The condensation reaction for _NOTP-N monomers was found to be 5–6 times slower than the analogous OTP derivatives. When the 5′-end nucleoside of a growing oligomer adopts a C3′-endo conformation, a conformational ‘clash’ with the incoming _NOTP-N monomer takes place, which is a main factor decreasing the repetitive yield of chain elongation. Although both isomers of N_NPSN′ were digested by the HINT1 phosphoramidase enzyme, the isomers hydrolyzed at a faster rate were tentatively assigned the R_P absolute configuration. This assignment is supported by X-ray analysis of the protected dinucleotide ^DMTdG^iBu_NPSMeT_OAc, which is P-stereoequivalent to the hydrolyzed faster P-diastereomer of dG_NPST.

Separated P-diastereomers of 3′-N-(2-thio-1,3,2-oxathiaphospholane) derivatives of 5′-O-DMT-3′-amino-2′,3′-dideoxy-ribonucleosides were used to prepare P-stereodefined N_NPSN′ dinucleotides and short NPS-, NPS/PO- and NPS/PS-oligomers.     

Effect of diluent on the extraction of europium(iii) and americium(iii) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA)

Solvent extraction of Eu³⁺ and Am³⁺via N,N,N′,N''-tetraoctyl diglycolamide (TODGA) dissolved in different molecular diluents was studied. The diluent types used in this work were primary and secondary alcohols, secondary ketones and alkanes. Effects of concentration of extracting agent, temperature, diluent type and its carbon chain length on the extractions were determined. Distribution ratios of Eu³⁺ and Am³⁺ showed high dependence on the diluent type as well as the carbon chain length within the same type of diluent. The highest distribution ratios for both Eu³⁺ and Am³⁺ as well as the separation factors of Eu³⁺ over Am³⁺ were observed in the alkane diluents. Unexpectedly high distribution ratios for Eu³⁺ and Am³⁺ were observed in polar diluents with 5 carbon atoms in the chain, clearly standing out against the general trends. It was found that Eu³⁺ and Am³⁺ extraction via TODGA is enthalpy driven in all the studied diluents and that extraction is more exothermic in alkane diluents. Analysis of the stoichiometry of the extracted complexes shows that the average ligand number of TODGA molecules in the extracted complex is lower for Am³⁺ compared to Eu³⁺ except for with alkane diluents.

Solvent extraction of Eu³⁺ and Am³⁺via N,N,N′,N''-tetraoctyl diglycolamide (TODGA) dissolved in different molecular diluents was studied.     

Computational studies on functionalized Janus MXenes MM′CT2, (M,M′ = Zr,Ti, Hf,M ≠ M′; T = –O, –F, –OH): photoelectronic properties and potential photocatalytic activities

Motivated by the successful synthesis of Janus monolayers of transition metal dichalcogenides (i.e., MoSSe), we computationally investigated the structural, electronic, optical, and transport properties of functionalized Janus MXenes, namely MM′CT₂ (M, M′ = Zr, Ti, Hf, M ≠ M′, T = –O, –F, –OH). The results of the calculations demonstrate that five stable O-terminated Janus MXenes (ZrTiCO₂-I, ZrHfCO₂-I, ZrHfCO₂-III, HfTiCO₂-I, and HfTiCO₂-III), exhibit modest bandgaps of 1.37–1.94 eV, visible-light absorption (except for ZrHfCO₂-I), high carrier mobility, and promising oxidization capability of photoinduced holes. Additionally, their indirect-gap, spatially separated electron–hole pairs, and the dramatic difference between the mobilities of electrons and holes could significantly limit the recombination of photoinduced electron–hole pairs. Our results indicate that the functionalized Janus MXene monolayers are ideal and promising materials for application in visible light-driven photocatalysis.

The functionalized Janus MXene monolayers: ideal and promising materials for use in visible light-driven photocatalysis.     

Structure-Activity Relationships Among a Group of 7-[α-(N, N′-Substituted-Amidinothio)-Acetamido] Cephalosporanic Acids

Structure-activity relationships were examined for a number of 7-[alpha-(N,N'-substituted-amidinothio)-acetamido] cephalosporanic acids, including several wherein the amidino group was cyclized into six, seven, and eight-membered rings and a series wherein alkyl, cycloalkyl, alkenyl, and alkynyl radicals were substituted on the nitrogens of the noncyclized amidino group. Derivatives containing an unsubstituted cyclized amidino group had comparable antibacterial activity in vitro and in general had a spectrum of activity broader than that of cephalothin, especially against cephalothin-resistant strains of Escherichia, Klebsiella, and Proteus. When administered parenterally, the cephalosporin with the six-membered cyclized amidino group was as effective as cephalothin in experimental infections of mice produced by cephalothin-sensitive gram-negative organisms and more efficacious in infections caused by cephalothin-resistant strains. Among the cephalosporins with noncyclized amidino groups, those with an ethyl substituent on one of the nitrogens and a C(2)-C(4) alkyl radical, particularly propyl on the other, were the most active. They not only had a better profile of activity in vitro than cephalothin and the cephalosporin derivatives having a cyclized amidino group, but were also more efficacious in infections of mice.     

Coordination properties of N,N′-bis(5-methylsalicylidene)-2-hydroxy-1,3-propanediamine with d- and f-electron ions: crystal structure,stability in solution,spectroscopic and spectroelectrochemical studies

Template reaction between 5-methylsalicylaldehyde and 2-hydroxy-1,3-propanediamine in the presence of copper ion led to dinuclear and mononuclear copper(ii) complexes [Cu₂L(CH₃COO)(CH₃OH)](CH₃OH) (1) and [CuHL](CH₃OH) (2), where H₃L is N,N′-bis(5-methylsalicylidene)-2-hydroxy-1,3-propanediamine. The result of the reactions between 5-methylsalicylaldehyde and 2-hydroxy-1,3-propanediamine in the presence of lanthanide ions and/or copper(ii) ion was N,N′-bis(5-methylsalicylidene)-2-hydroxy-1,3-propanediamine (H₃L B) or [CuHL](CH₃OH) (2), respectively. Structures of the compounds were determined by single-crystal X-ray diffraction and physicochemical methods. The microstructures and phase compositions of crystals were studied by scanning electron microscopy (SEM). In dinuclear complex [Cu₂L(CH₃COO)(CH₃OH)](CH₃OH) (1), two copper(ii) ions are bond to one H₃L ligand and one acetate ion. Coordination modes of the two copper centers are different: the geometry of copper 1 is almost ideal square-planar, while that for copper 2 can be described as tetragonal pyramidal. In complex [CuHL](CH₃OH) (2), the copper(ii) ion is four coordinated and the coordination, rather than square-planar, can be described as flattened tetrahedral. Formation of complexes between copper(ii) or lanthanide ions with N,N′-bis(5-methylsalicylidene)-2-hydroxy-1,3-propanediamine (H₃L) was also studied in solution by pH potentiometry. It should be mentioned that the complexes of lanthanide ions exist only in solution. Additionally, the salen-type ligand H₃L and its dinuclear and mononuclear copper(ii) complexes were studied by cyclic voltammetry, and their spectroelectrochemical properties were examined.

The self-assembled metal-promoted synthesis and properties of N,N′-bis(5-methylsalicylidene)-2-hydroxy-1,3-propanediamine (H₃L) complexes with d- and f-metal ions are described.     

Poly[2,2′-(4,4′-bipyridine)-5,5′-bibenzimidazole] functionalization of carbon black for improving the oxidation stability and oxygen reduction reaction of fuel cells

The rapid oxidation of carbon black (CB) is a major drawback for its use as a catalyst support in polymer electrolyte fuel cells. Here, we synthesize poly[2,2′-(4,4′-bipyridine)-5,5′-bibenzimidazole] (BiPyPBI) as a conducting polymer and use it to functionalize the surface of CB and homogenously anchor platinum metal nanoparticles (Pt-NPs) on a CB surface. The as-prepared materials were confirmed by different spectroscopic techniques, including nuclear magnetic resonance spectroscopy, energy-dispersive X-ray, thermal gravimetric analysis, and scanning-transmittance microscopy. The as-fabricated polymer-based CB catalyst showed an electrochemical surface area (ECSA) of 63.1 cm² mg_Pt⁻¹, giving a catalyst utilization efficiency of 74.3%. Notably, the BiPyPBI-based CB catalyst exhibited remarkable catalytic activity towards oxygen reduction reactions. The onset potential and the diffusion-limiting current density reached 0.66 V and 5.35 mA cm⁻², respectively. Furthermore, oxidation stability testing showed a loss of only 16% of Pt-ECSA for BiPyPBI-based CB compared to a 36% loss of Pt-ECSA for commercial Pt/CB after 5000 potential cycles. These improvements were related to the synergetic effect between the nitrogen-rich BiPyPBI polymer, which promoted the catalytic activity through the structural nitrogen atoms, and demolished the degradation of CB via the wrapping process.

The rapid oxidation of carbon black (CB) is a major drawback for its use as a catalyst support in polymer electrolyte fuel cells.     

Synthetic strategy and structure–activity relationship (SAR) studies of 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1, Lificiguat): a review

Since 1994, YC-1 (Lificiguat, 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of hypoxia-inducible factor-1 (HIF-1) and NF-κB. Recently, Riociguat®, the first soluble guanylate cyclase (sGC) stimulator drug used to treat pulmonary hypertension and pulmonary arterial hypertension, was derived from the YC-1 structure. In this review, we aim to highlight the synthesis and structure–activity relationships in the development of YC-1 analogs and their possible indications.

Since 1994, YC-1 (Lificiguat) has been synthesized, and many targets for special bioactivities have been explored, such as stimulation of platelet-soluble guanylate cyclase, indirect elevation of platelet cGMP levels, and inhibition of HIF-1 and NF-κB.     

Enzymatic synthesis of biobased aliphatic–aromatic oligoesters using 5,5′-bis(hydroxymethyl)furoin as a building block

5,5′-Dihydroxymethyl furoin (DHMF) is a novel biobased difuranic polyol scaffold, achievable from the benzoin condensation of 5-hydroxymethylfurfural (HMF), which has recently been employed as a monomer for the preparation of cross-linked polyesters and polyurethane. Its upgrading by means of enzymatic reactions has not yet been reported. Here we demonstrated that Candida antarctica lipase B (CALB) is a suitable biocatalyst for the selective esterification of the primary hydroxyl groups of DHMF. Exploiting this enzymatic activity, DHMF has been reacted with the diethyl esters of succinic and sebacic acids obtaining fully biobased linear oligoesters with number-average molecular weight around 1000 g mol⁻¹ and free hydroxyl groups on the polymer backbone. The structures of the DHMF-diacid ethyl ester dimers and of the oligomers were elucidated by NMR and MS analyses.

Fully bio-based linear oligoesters were obtained by the unprecedented enzymatic polymerization of 5,5′-bis(hydroxymethyl)furoin with succinic and sebacic acid diethyl esters.     

Antiherpesvirus Activities of (1′S,2′R)-9-{[1′,2′-Bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine (A-5021) in Cell Culture

Antiherpetic activity of (1′S,2′R)-9-{[1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl}guanine (A-5021) was compared with those of acyclovir (ACV) and penciclovir (PCV) in cell cultures. In a plaque reduction assay using a selection of human cells, A-5021 showed the most potent activity in all cells. Against clinical isolates of herpes simplex virus type 1 (HSV-1, n = 5) and type 2 (HSV-2, n = 6), mean 50% inhibitory concentrations (IC₅₀s) for A-5021 were 0.013 and 0.15 μg/ml, respectively, in MRC-5 cells. Corresponding IC₅₀s for ACV were 0.22 and 0.30 μg/ml, and those for PCV were 0.84 and 1.5 μg/ml, respectively. Against clinical isolates of varicella-zoster virus (VZV, n = 5), mean IC₅₀s for A-5021, ACV, and PCV were 0.77, 5.2, and 14 μg/ml, respectively, in human embryonic lung (HEL) cells. A-5021 showed considerably more prolonged antiviral activity than ACV when infected cells were treated for a short time. The selectivity index, the ratio of 50% cytotoxic concentration to IC₅₀, of A-5021 was superior to those of ACV and PCV for HSV-1 and almost comparable for HSV-2 and VZV. In a growth inhibition assay of murine granulocyte-macrophage progenitor cells, A-5021 showed the least inhibitory effect of the three compounds. These results show that A-5021 is a potent and selective antiviral agent against HSV-1, HSV-2, and VZV.     

N,N-Dioctadecyl-N′,N′-Bis(2-Hydroxyethyl) Propanediamine: Antiviral Activity and Interferon Stimulation in Mice

CP-20,961, N,N-dioctadecyl-N', N'-bis(2-hydroxyethyl)propanediamine, is an antiviral drug with low acute toxicity in mice. Parenteral injection of this compound protected mice against lethal infections with encephalomyocarditis and Semliki Forest viruses and effectively suppressed pox formation by vaccinia infection. Maximal antiviral effects were observed when CP-20,961 was administered 6 to 12 h before infection. An interferon detected in plasma 12 to 20 h after the drug was given appeared to mediate these effects. Comparison of the minimal effective and lethal doses in mice established a therapeutic index of 300.     

The effect of octahedral distortions on the electronic properties and magnetic interactions in O3 NaTMO2 compounds (TM = Ti–Ni & Zr–Pd)

The interplay between the coordination environment and magnetic properties in O3 layered sodium transition metal oxides (NaTMO₂) is a fascinating and complex problem. Through detailed and comprehensive density functional investigations on O3 NaTMO₂ compounds, we demonstrate that the TM ions in O3 NaMnO₂, NaFeO₂ and NaCoO₂ adopt a high spin state. Structurally, NaMnO₂ and NaPdO₂ undergo Jahn–Teller distortions while NaNbO₂ undergoes puckering distortion. Furthermore, in addition to Jahn–Teller distortion, NaPdO₂ exhibits charge disproportionation as it contains Pd²⁺, Pd³⁺ and Pd⁴⁺ species. These distortions stabilize the inter-plane ferromagnetism. Additionally, the inter-plane ferromagnetic coupling is stabilized by kinetic p–d exchange mechanism in undistorted NaCoO₂, NaNiO₂ and NaTcO₂. The intra-plane coupling in this family of compounds on the other hand was found to be generally weak. Only NaMnO₂, NaNiO₂ and NaTcO₂ are predicted to show bulk ferromagnetism with estimated Curie temperatures below ∼50 K.

Although O3 sodium transition metal oxides (NaTMO₂) share many similarities, they still differ from one another by some fine structural details.     

Closed-shell d10–d10 in [AuCl(CNR)]n and [AuCl(CO)]n (n = 1, 2; R = –H, –CH3, –Cy) complexes: quantum chemistry study of their electronic and optical properties

The electronic structure and spectroscopic properties of [AuCl(CNR)] and [AuCl(CO)] (R = –H, –CH₃, –Cy) complexes with d¹⁰–d¹⁰ type interactions were studied at the post-Hartree–Fock (MP2, SCS-MP2, CCSD(T)) and density functional theory levels. It was found that the nature of the intermetal interactions is consistent with the presence of an electrostatic (dipole–dipole) contribution and a dispersion-type interaction. The absorption spectra of these complexes were calculated using the single excitation time-dependent (TD) method at the DFT and SCS-CC2 levels. The calculated values are in agreement with the experimental range, where the absorption and emission energies reproduce the experimental trends, with large Stokes shifts. According to this, intermetallic interactions were found to be mainly responsible for the metal–metal charge transfer (MMCT) electronic transitions among the models studied.

The [AuCl(CNR)] and [AuCl(CO)] (R = –H, –CH₃, –Cy) complexes were modeled and their electronic and optical properties described.     

Syntheses,characterization and properties of three coordination polymers with interpenetrating structures comprising 4,4′-(1H-1,2,4-triazol-1-yl)methylene-bis(benzonic acid)

Three new coordination polymers (CPs), {[Pb(tmdb)](H₂O)}_n (1), {[Zn(tmdb)(bimb)_0.5]}_n (2) and {[Zn₃(tmdb)₃(bpmb)_1.5](H₂O)₆}_n (3) (H₂tmdb = 4,4′-(1H-1,2,4-triazol-1-yl)methylene-bis(benzonic acid), where bpmb = 1,4-bis(pyridin-4-ylmethoxy)benzene and bimb = 1,4-bis(imidazoly-1-yl)benzene), have been solvothermally or hydrothermally synthesized. Compound 1 is a 2D network with the point symbol (4·6·8)(4·6²) and compound 2 is a 4-fold interpenetrating 3D network with spiral chains. The topological type of 2 is dmc (topos&RCSR.ttd) with the point symbol (4·8²)(4·8⁵). Compound 3 is a 3-fold interpenetrating 3D network with the point symbol (6³)₂(8·6⁵)₂(10·6²)(8·10·6⁴). The electrochemiluminescence (ECL) behaviors of 2 and 3 were studied. The applications of CP 2 and 3 in detecting ions were explored, and the results show that they can be used as fluorescent probes to selectively detect and identify Fe³⁺ ions in water. In addition, the applications of CP 2 and 3 in the adsorption and separation of dyes were researched. Furthermore, the gas adsorption of 3 was studied.

The synthesis and characterization of three compounds with H₂tmdb ligands is reported. The polymers were analyzed using PXRD, IR, TGA and fluorescence spectrometry.     

Synthesis of new N,N′-Pd(Pt) complexes based on sulfanyl pyrazoles,and investigation of their in vitro anticancer activity

The synthesis of new N,N′-mononuclear bi-ligand Pd(ii) and tri-ligand Pt(ii)complexes bearing sulfanyl(phenyl, benzyl, cyclohexyl, 4-hydroxyphenyl)3,5-dimethyl-1H-pyrazole ligands has been carried out. The obtained compounds were studied for apoptosis-inducing activity and effect on the cell cycle for Jurkat, K562, and U937 neoplastic cell cultures and conditionally normal human embryonic kidney HEK293 cells. The cells showed the highest sensitivity to platinum and palladium complexes in comparison with ligands and cisplatin. The cytotoxic properties are enhanced for compounds with cyclohexyl substituents at the S-atom in sulfanyl pyrazoles and complexes.

Efficient cytostatics against Jurkat, K562 and U937 neoplastic cell lines were found among the synthesized new Pd(ii) and Pt(ii)complexes (six examples) with sulfanyl-1H-pyrazole ligands using in vitro assay.     

Transformation of the coordination nanostructures of 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl) tribenzoic acid molecules on HOPG triggered by the change in the concentration of metal ions

The modulation effects of Cu²⁺/Fe³⁺ ions on the hydrogen-bonded structure of 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl) tribenzoic acid (TATB) on a HOPG surface have been investigated at the liquid–solid interface by scanning tunneling microscopy (STM). STM observations directly demonstrated that the self-assembled honeycomb network of TATB has been dramatically transformed after introducing CuCl₂/FeCl₃ with different concentrations. The metal–organic coordination structures are formed due to the incorporation of the Cu²⁺/Fe³⁺ ions. Interestingly, a Cu²⁺ ion remains coordinated to two COOH groups and only the number of COOH groups involved in coordination doubles when the concentration of Cu²⁺ ions doubled. A Fe³⁺ ion changes from coordination to three COOH groups to two COOH groups after increasing the concentration of Fe³⁺ ions in a mixed solution. Such results suggest that the self-assembled structures of TATB molecules formed by metal–ligand coordination bonds can be effectively adjusted by regulating the concentration of metal ions in a mixed solution, which has rarely been reported before. It explains that the regulatory effect of concentration leads to the diversity of molecular architectures dominated by coordination bonds.

A Cu²⁺ ion maintains coordination with two COOH groups, while a Fe³⁺ ion changes from coordination with three to two COOH groups after increasing the concentration of Cu²⁺/Fe³⁺ ions.     

Tetrakis(ethyl-4(4-butyryl)oxyphenyl)porphyrinato zinc complexes with 4,4′-bpyridin: synthesis,characterization, and its catalytic degradation of Calmagite

This work reports on the synthesis and characterization of a new porphyrins complex:[Zn(TEBOP)(4,4′-bpy)](4,4′-bipyridine)(5,10,15,20-(tetraethyl-4(4-butyryl)oxyphenyl)porphyrinato)zinc(ii) (3). Single crystal X-ray diffraction, photophysical and electrochemical characteristics were studied. The prepared complex, penta-coordinated zinc(ii) porphyrin derivatives shows moderate ruffling distortion and the zinc atom is nearly planar with the porphyrin core. Tolyl and ethyl-4(4-butyryl)oxyphenyl) moieties at the meso positions present a bathochromic shift of the absorption bands, and a notable increase in the absorption coefficient of the Q(0,0) and Q(0,1) bands was observed with a higher fluorescence quantum yield and lifetime compared with the free base porphyrin. The electrochemical investigation shows a reversible reduction of the synthesized complexes. The catalytic power and the adsorption properties of the prepared complexes were studied for Calmagite degradation, an azoic organic dye. The results reveal that the studied compounds could be used as catalysts for the decolourisation of dyes in the presence of H₂O₂.

This work reports on the synthesis and characterization of a new porphyrins complex:[Zn(TEBOP)(4,4′-bpy)](4,4′-bipyridine)(5,10,15,20-(tetraethyl-4(4-butyryl)oxyphenyl)porphyrinato)zinc(ii)(3).     

Selective Inhibition of Herpesvirus Deoxyribonucleic Acid Synthesis by Acycloguanosine, 2′-Fluoro-5-Iodo-Aracytosine, and (E)-5-(2-Bromovinyl)-2′-Deoxyuridine

The selectivity of inhibition of herpesvirus deoxyribonucleic acid synthesis by acycloguanosine, 2′-fluoro-5-iodo-aracytosine, and (E)-5-(2-bromovinyl)-2′-deoxyuridine was determined by isopycnic banding of ³²P-labeled deoxyribonucleic acid from herpesvirus-infected and uninfected cells.     

Synthesis,gene silencing activity,thermal stability,and serum stability of siRNA containing four (S)-5′-C-aminopropyl-2′-O-methylnucleosides (A,adenosine; U,uridine; G,guanosine; and C,cytidine)

Herein, we report the synthesis of (S)-5′-C-aminopropyl-2′-O-methyladenosine and (S)-5′-C-aminopropyl-2′-O-methylguanosine phosphoramidites and the properties of small interfering RNAs (siRNAs) containing four (S)-5′-C-aminopropyl-2′-O-methylnucleosides (A, adenosine; U, uridine; G, guanosine; and C, cytidine). The siRNAs containing (S)-5′-C-aminopropyl-nucleosides at the 3′- and 5′-regions of the passenger strand were well tolerated for RNA interference (RNAi) activity. Conversely, the (S)-5′-C-aminopropyl modification in the central region of the passenger strand decreased the RNAi activity. Furthermore, the siRNAs containing three or four consecutive (S)-5′-C-aminopropyl-2′-O-methylnucleosides at the 3′- and 5′-regions of the passenger strand exhibited RNAi activity similar to that of the corresponding 2′-O-methyl-modified siRNAs. Finally, it was observed that (S)-5′-C-aminopropyl modifications effectively improved the serum stability of the siRNAs, compared with 2′-O-methyl modifications. Therefore, (S)-5′-C-aminopropyl-2′-O-methylnucleosides would be useful for improving the serum stability of therapeutic siRNA molecules without affecting their RNAi activities.

(S)-5′-C-Aminopropyl-2′-O-methylnucleosides would be useful for improving the serum stability of therapeutic siRNA molecules without affecting their RNAi activities.